Let `git cl format` format .mm files too.

depot_tools/git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 from distutils.version import LooseVersion
@@ skipping 2288 matching lines @@
       [f.LocalPath() for f in
           cl.GetChange(base_branch, None).AffectedFiles()],
       change.RepositoryRoot(), author,
       fopen=file, os_path=os.path, glob=glob.glob,
       disable_color=options.no_color).run()
 
 
 @subcommand.usage('[files or directories to diff]')
 def CMDformat(parser, args):
   """Runs clang-format on the diff."""
-  CLANG_EXTS = ['.cc', '.cpp', '.h']
+  CLANG_EXTS = ['.cc', '.cpp', '.h', '.mm']
   parser.add_option('--full', action='store_true',
                     help='Reformat the full content of all touched files')
   parser.add_option('--dry-run', action='store_true',
                     help='Don\'t modify any file on disk.')
   opts, args = parser.parse_args(args)
 
   # git diff generates paths against the root of the repository.  Change
   # to that directory so clang-format can find files even within subdirs.
   rel_base_path = RunGit(['rev-parse', '--show-cdup']).strip()
   if rel_base_path:
@@ skipping 117 matching lines @@
         ('AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
           'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
 
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   colorama.init()
   sys.exit(main(sys.argv[1:]))